@ the ronin: A lot of supercars are using the exhaust to fill the vacuum that forms at speed, just rear of the car. All that wind rushing overhead creates an area of low pressure at the back, that causes drag when the air rushes into fill it. Or a dirty door on the back of a semi after a rain storm.

By filling this space with exhaust gasses, you get less drag. More speed: zero negatives. So maybe money is buying brains after all?

Maybe take that money used for buying brains and use it for the books on automotive aerodymamics to show you how wrongly the money was spent.... Maybe return the faulty brains if you can...and apply it to the proper application...Exhaust Driven Diffusers « Scarbsf1's Blog